Ru-Catalyzed Asymmetric Hydrogenation of 3-Oxoglutaric Acid Derivatives via Solvent-Assisted Pinpoint Recognition of Carbonyls in Close Chemical Propinquity
摘要:
Upon comparison of hydrogenation rates of various beta-ketocarboxylic acid derivatives, beta-ketoamides were found to be hydrogenated slightly faster than beta-ketoesters in EtOH in the presence of [RuCl(benzene)(S)-SunPhos]Cl at 70 degrees C with 20 bar of hydrogen. In THF these differences were so sharpened that beta-ketoamides were hydrogenated even faster than In EtOH while the esters were extremely slow. Based on these findings, a series of 3-oxoglutaric acid derived with ester and amide moieties on the two ends were hydrogenated to 3-hydroxyl products with high enantioselectivities.
作者:Zhiguo Zhang、Songnan Wang、Chunfang Hu、Nana Ma、Guisheng Zhang、Qingfeng Liu
DOI:10.1016/j.tet.2018.11.023
日期:2018.12
A selective copper(I)-catalyzed benzylic C(sp3)–H geminal difunctionalization reaction of a benzylic-type sp3 carbon was developed. This novel strategy allowed simultaneous introduction of amide and hydroxyl group in a highly selective and efficient way via successive oxidative intramolecular amidation and hydroxylation. This method was also applied to the synthesis of 3-hydroxy-2,3-dihydro-1H-pyrrolo[3
开发了选择性铜(I)催化的苄型sp 3碳的苄基C(sp 3)–H双子双官能化反应。这种新颖的策略允许通过连续的氧化性分子内酰胺化和羟基化以高度选择性和有效的方式同时引入酰胺和羟基。该方法还适用于从容易获得的3-甲基-N-取代的喹喔啉-2-羧酰胺以中度到良好的程度合成3-羟基-2,3-二氢-1 H-吡咯并[3,4- b ]喹喔啉酮。产量。吡咯并[5,4- b]的五元环状半胱氨酸部分]喹喔啉酮可以用作随后转化为其他有用的官能团的中间体。
Metal-Free Michael-Addition-Initiated Three-Component Reaction for the Regioselective Synthesis of Highly Functionalized Pyridines: Scope, Mechanistic Investigations and Applications
and completely regioselective three-componentsynthesis of highly functionalizedpyridines from 1,3-dicarbonyl derivatives and Michael acceptors has been achieved. Activated Michael acceptors, that is, β,γ-unsaturated α-oxo carbonyl derivatives, were utilized, allowing substitution at the 4-position and remarkable functional diversity at the 2-position of the pyridine ring. The scope and limitations
Synthesis, Characterization, and Cytotoxic Evaluation of Some Newly Substituted Diazene Candidates
作者:Mohamed El-Naggar、Abdel-Nasser El-Shorbagi、Dina H. Elnaggar、Abd El-Galil E. Amr、Mohamed A. Al-Omar、Elsayed A. Elsayed
DOI:10.1155/2018/3626824
日期:2018.11.1
5-amino-2-hydroxybenzoate or 1-aminonaphthalene by using NaNO2 in the presence of HCl afforded diazonium salt derivatives 2 and 5, which were treated with substituted imino or substituted amino derivatives, to give the corresponding substituted amino-pent-2-en-3-yl-diazenylbenzoate 4a–k or 2-substituted-1-(naphthalen-1-yl)diazene derivatives 6a–h, 7a,b, and 8a,b. All the synthesized compounds were
In Situ Generated TEMPO Oxoammonium Salt Mediated Tandem Cyclization of β-Oxoamides with Amine Hydrochlorides for the Synthesis of Pyrrolin-4-ones
作者:Xuna Zhao、Tong-Xin Liu、Nana Ma、Guisheng Zhang
DOI:10.1021/acs.joc.7b00686
日期:2017.6.16
A novel in situ generated TEMPO oxoammonium salt mediated one-pot tandem reaction has been developed for the straightforward construction of pyrrolin-4-ones from readily available β-oxoamides with amine hydrochlorides. The reaction tolerates various functional groups and represents a reliable method for the synthesis of highly substituted pyrrolin-4-ones in good yields under mild conditions. Detailed
of new chiral N -phosphinyl β-enamino esters and amides were successfully prepared with excellent Z -stereoselectivity ( Z / E > 99:1 in nearly all cases). Group-assisted purification chemistry proved to be an efficient method for the asymmetric reduction of the resulting β-enamino esters/amides to give enantiopure β-amino esters/amides. The asymmetric reduction can be controlled efficiently by using